The invention relates generally to acoustic processing, and more particularly to a method and system for making acoustic scattering measurements in a medium and processing same in order to determine variances in multiple features of the medium.
Measurements of features of a medium are typically accomplished with sensors placed in the medium. For example, oceanographers often place sensors in the water to record time-changing features such as temperature, salinity, etc. This requires the invasive placement of a sensor(s) in the medium of interest. Such placement is time consuming and can disrupt the medium in the region of interest.
Accordingly, it is an object of the present invention to provide a method and system for making non-invasive measurements of one or more of a medium""s features.
Another object of the present invention is to provide a method and system for making non-invasive acoustic measurements and processing same in order to determine variances in one or more features of a media.
Still another object of the present invention is to provide a method and system for using acoustic scattering measurement techniques and for processing of such measurements to determine variances in multiple features of a medium.
Yet another object of the present invention is to provide a method and system for using acoustic scattering measurement techniques and for processing of such measurements to determine variances in water temperature and salinity.
A further object of the present invention is to provide a method and system for using acoustic scattering measurement techniques and for processing of such measurements to determine variances in sound speed and density of human tissue.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, a method is provided for determining multiple feature variances in a medium. A scattering direction is selected relative to a region of interest in a medium. Acoustic sources are positioned on one side of the selected scattering direction. Acoustic receivers are positioned on an opposite side of the selected scattering direction such that, for each acoustic source, there is a corresponding acoustic receiver located at a mirror-imaged position relative to the selected scattering direction. As a result, a Bragg scattering wave vector associated with each acoustic source/receiver pair is parallel to the selected scattering direction. Each acoustic source is operated at a unique time to direct a broadband ultrasonic pulse at the region of interest. An acoustic scattered wave reflecting from the region of interest is detected as a waveform at the acoustic receiver that corresponds to the acoustic source that emitted the broadband ultrasonic pulse. Each waveform is digitized and then converted to the frequency domain to form a spectral waveform. A band of Bragg wave a numbers is determined for each spectral waveform. Variations in multiple features of the medium are then determined by solving a complex acoustic scatter relationship as a function of the band of Bragg wave numbers associated with the particular source/receiver pair.